[c-nsp] Bridging ATM on 7206? (anything goes)

[Bruce Robertson]

Nathan wrote:
> On Fri, Oct 24, 2008 at 5:24 PM, Bruce Robertson <bruce at greatbasin.net> wrote:
>   
>> If I remember correctly, the 1751 supports L2TPv3.  You could add another
>> Ethernet interface to the 1751 (the WIC-4ESW is handy for that, or
>> WIC-1ENET), insert it between the 871 and customer, and bridge the Ethernets
>> through, without killing MTU.
>>     
>
> Sounds doable. So with a 1751, I should be able to do an xconnect on
> each of my two interfaces, and thereby string two L2TPv3 pseudowires
> beteen my sites?
>   
That's correct.  It gets messier if you need to tie multiple sites into 
one broadcast domain, but it's still doable.  The only difference there 
is that you need to terminate all the L2TPv3 pseudowires at your central 
site, burning a router Ethernet interface for each one, and then tie 
them all together with a switch.  It doesn't scale well.  If there's a 
simpler way, hopefully someone on the list will point it out.
> With two 1751s I don't suppose I'll need the 871s though (my need is
> connecting LANs site A - my871 - ethernet - ethernet2ATMconverter -
> ATM - 7200 - ATM - ethernet2ATMconverter - ethernet - my871 - LANs
> site B, where the LANs are currently two untagged RJ45s on each side
> but could be a single RJ45 with a dot1q trunk).
>   
Yes, assuming the ATM is DSL, the 1751 can do the DSL directly. You 
wouldn't need the extra Ethernet interface in that case.  I don't know 
anything about 871s; are you using any special features that the 1751 
can't do?

BTW, you'll need IOS 12.4 on the 1751 to do the L2TPv3.
> In your opinion, no way of doing it with L2TP on my 871s?
>   
Dunno, I tend to avoid L2TP non-v3.  v3 has worked very well for us.
> --
> Thanks for your help,
> Nathan
>
>